Lensed tunable Fabry-Perot (“FP”) interferometers (“FPIs”) have long played an important role in optical spectrum measurements in physics, chemistry, astronomy and other diverse scientific fields. Miniature lensed FPIs adapted to fiber optical systems can provide medium resolution tuning (finesse=100). Lensless fiber FPIs (“FFPIs”), however, can perform at resolutions greater than 500 for tuning functions in optical fiber systems. Such high performance tunable FFPIs have enabled interrogator systems for accurately measuring wavelength responses of passive or active fiber optics devices.
In many technical applications, precision wavelength measurements must be made in the field, oftentimes far distant and removed from precision calibration resources. It is therefore necessary to have a reliable and accurate on-site wavelength reference that can be used for any optical band that may be of interest. This is especially true for implementing the many optical instruments of contemporary dense wavelength division multiplexing (“DWDM”) fiber optics networks, such as optical spectrum analyzers (“OSAs”), optical channel monitors (“OCMs”), dispersion measurement (“DM”) tools, and so forth.
Unfortunately, calibration sources under field conditions often are not available for all the wavelength bands of interest at the field location. In fact, available calibration sources frequently do not even fall within the limited range of a particular band that is currently identified for measurement in the field. Also lacking, in general, are optical spectrum analyzer and reference systems that have broad wavelength ranges and that can also utilize and benefit from the particular advantages of FP interferometers.
Thus, a need still remains for systems for broad- and inter-band multi-wavelength references, and in particular for such systems that employ FP interferometers for the measurement of wavelengths of light over broad and extended wavelength ranges. A more particular need exists for accurate wavelength references that can transfer a wavelength reference that is provided by an existing wavelength reference source to a different wavelength range of interest.
In view of the ever-increasing commercial competitive pressures, increasing consumer expectations, and diminishing opportunities for meaningful product differentiation in the marketplace, it is increasingly critical that answers be found to these problems. Moreover, the ever-increasing need to save costs, improve efficiencies, and meet such competitive pressures adds even greater urgency to the critical necessity that answers be found to these problems.
Solutions to these problems have been long sought but prior developments have not taught or suggested any solutions and, thus, solutions to these problems have long eluded those skilled in the art.